RF transceiver system with adjustable transmission parameters and methods for use therewith

ABSTRACT

A circuit includes a transceiver coupled to transmit an outbound signal in accordance with a plurality of transmit parameters to at least one remote station and receive an inbound signal from the at least one remote station. The transceiver detects a packet transmission failure, selects one of a plurality of transmission failure causes, and adjusts at least one of a plurality of transmit parameters, based on the selected one of the plurality of transmission failure causes.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present U.S. Utility Patent Application claims priority pursuant to35 U.S.C. §120, as a continuation, to U.S. Utility patent applicationSer. No. 11/731,239, entitled RF TRANSCEIVER SYSTEM WITH ADJUSTABLETRANSMISSION PARAMETERS AND METHODS FOR USE THEREWITH, filed on Mar. 29,2007, which is hereby incorporated herein by reference in its entiretyand made part of the present U.S. Utility Patent Application for allpurposes.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to data communications and in particularto improving performance of multiple network multiple protocolcommunication using a shared medium.

2. Description of the Related Art

Communication systems are known to support wireless and wire linedcommunications between wireless and/or wire lined communication devices.Such communication systems range from national and/or internationalcellular telephone systems to the Internet to point-to-point in-homewireless networks. Each type of communication system is constructed, andhence operates, in accordance with one or more communication standards.For instance, wireless communication systems may operate in accordancewith one or more standards including, but not limited to, IEEE 802.11b,IEEE 802.11g, IEEE 802.11a, Bluetooth, IEEE 802.16e, advanced mobilephone services (AMPS), digital AMPS, global system for mobilecommunications (GSM), code division multiple access (CDMA), localmulti-point distribution systems (LMDS), multi-channel-multi-pointdistribution systems (MMDS), and/or variations thereof. Wirelesscommunication devices exploit electromagnetic wave propagation totransmit data. Such communication devices include a radio receiverand/or a radio transmitter.

The radio transmitter usually includes a data modulation stage, one ormore frequency conversion stages, and a power amplifier coupled to theantenna. The data modulation stage converts (modulates) raw data bitsinto baseband signal in accordance with a particular wirelesscommunication standard. The frequency conversion stages convert basebandsignal into a radio frequency (RF) signal. The power amplifier amplifiesthe RF signal and an antenna radiates RF signal as an electromagneticfield.

The radio receiver is coupled to an antenna and usually includes lownoise amplifier, one or more frequency conversion stages, one or morefiltering stages and a data recovery stage. The antenna convertselectromagnetic field into an electrical RF signal, the low noiseamplifier amplifies the electrical RF signal, the frequency conversionstages convert RF signal into a baseband signal, the filtering stagesattenuate all unwanted frequency components and the data recovery stagerecovers (demodulates) raw data from the filtered signal in accordancewith a particular communication standard.

The electromagnetic field radiated at the receive antenna is inverselyproportional to the distance from the transmit antenna. The electricalRF signal produced by the antenna is coupled with the noise signalcaused by the random thermal motion of the electrons. This noise maycause errors in the data recovery process. The probability of such errordepends on the signal to noise ratio (SNR) and the type of modulationused in the data transmission. The higher the SNR ratio, the lower theprobability of the bit error. The reliability of the wireless link isoften measured by the bit error rate (BER) or packet error rate (PER).

Wireless standards often allow transmitter to use more than one way tomodulate the raw data. For example wireless communication devices thatare compliant with 802.11g standard can communicate with each otherusing data rates of 1, 2, 5.5, 6, 9, 11, 12, 18, 24, 36, 48 and/or 54Mbps (megabits per second). Usually the higher the data rate the higherthe SNR needed to achieve equivalent BER or PER.

To maintain a reliable data connection at the highest possible data ratethe transmitter usually employs a dynamic transmission adaptationalgorithm. Such algorithm usually reduces the data rate for wirelesscommunication when number of unsuccessful attempts to transmit thepacket reaches a certain threshold. In an environment where the thermalnoise is the only source of demodulating errors this algorithm convergesto the highest data rate supported by the wireless link.

As is known, differing standards sometimes use the same communicationmedium (e.g., allocated radio frequency spectrum, wired connections,etc.) due to a finite amount of communication medium. For example, bothBluetooth and IEEE 802.11g use the 2.4 GHz spectrum. As long ascommunication systems that are compliant with differing standards thatshare a communication medium do not physically overlap, the systemsoperate without interference from each other. However, if thecommunication systems do physically overlap, they might interfere witheach other, degrading the performance of both systems. For example, if aBluetooth pico-net physically overlaps with an IEEE 802.11b local areanetwork, simultaneous use of the 2.4 GHz spectrum might causeinterference that can cause both transmissions to fail.

Further a single device can be capable of operating in two modes (e.g.Bluetooth and WLAN or WLAN & WiMax) such that operation of the device inone mode could preclude simultaneous operation in the other mode,particularly if one or more shared circuit components are used toimplement these two modes of operation. For instance, if the device isoperating in a Bluetooth mode, 802.11g transmissions directed to thedevice could fail and vice versa.

For transmission with the same amount of data, the probability of theoverlapping medium use is higher for lower data rates as such packetsrequire longer time to transmit. For the cases where transmission faileddue to the interference from another network using the same medium ordue to transmissions directed to a multimode device that uses sharedcircuit components, the regular dynamic transmission adaptationalgorithm employed by the transmitter results in lowering the data rate,increasing the packet transmission time thus further increasing theprobability of the medium access collisions. Other disadvantages of theprior art will be apparent to one skilled in the art when presented thedisclosure herein.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to apparatus and methods of operationthat are further described in the following Brief Description of theDrawings, the Detailed Description of the Invention, and the claims.Other features and advantages of the present invention will becomeapparent from the following detailed description of the invention madewith reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 presents a pictorial representation of a wireless network 111 inaccordance with an embodiment of the present invention.

FIG. 2 is a schematic block diagram of a wireless communication device121, 123, 125 or 127 in accordance with the present invention.

FIG. 3 is a schematic block diagram of a wireless access point 110 inaccordance with the present invention.

FIG. 4 is a schematic block diagram of an RF transceiver 125 inaccordance with the present invention.

FIG. 5 is a time diagram in accordance with an embodiment of the presentinvention.

FIG. 6 is a time diagram in accordance with an embodiment of the presentinvention.

FIG. 7 is a flowchart representation of a method in accordance with anembodiment of the present invention.

FIG. 8 is a flowchart representation of a method in accordance with anembodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 presents a pictorial representation of a wireless network 111 inaccordance with an embodiment of the present invention. The wirelessnetwork 111 includes an access point 110 that is coupled to packetswitched backbone network 101. The access point 110 managescommunication flow over the wireless network 111 destined for andoriginating from each of communication devices 121, 123, 125 and 127.Via the access point 110, each of the communication devices 121, 123,125 and 127 can access service provider network 105 and Internet 103 to,for example, surf web-sites, download audio and/or video programming,send and receive messages such as text messages, voice message andmultimedia messages, access broadcast, stored or streaming audio, videoor other multimedia content, play games, send and receive telephonecalls, and perform any other activities, provided directly by accesspoint 110 or indirectly through packet switched backbone network 101.

Access point 110 communicates real-time data and/or non-real-time datawirelessly with communication devices 121, 123, 125 and 127 overwireless network 111. In an embodiment of the present invention, one ormore of the communication devices 121, 123, 125 and 127 are multimodeshared frequency devices. In particular, the wireless network 111operates with a first wireless communication path that shares a commonfrequency spectrum with a second wireless communication path used by oneor more of the communication devices 121, 123, 125 and 127 whenoperating in an alternative communication mode, and further, thesedevices operate with shared circuit components or other limitations thatotherwise preclude the operation of these devices in both communicationmodes simultaneously. The first and second wireless communication pathscan operate in accordance with wireless network protocols such as IEEE802.11, Bluetooth, Ultra-Wideband (UWB), WIMAX, or other wirelessnetwork protocols, a wireless telephony data/voice protocol such asGlobal System for Mobile Communications (GSM), General Packet RadioService (GPRS), Enhanced Data Rates for Global Evolution (EDGE),Personal Communication Services (PCS), or other mobile wireless protocolor other wireless communication protocol, either standard orproprietary.

In an embodiment of the present invention, the communication devices121, 123, 125 and 127 can be personal computers, laptops, PDAs, mobilephones, such as cellular telephones, devices equipped with wirelesslocal area network or Bluetooth transceivers, FM tuners, TV tuners,digital cameras, digital camcorders, or other devices that eitherproduce, process or use audio, video signals or other data orcommunications. In operation, the communication devices include one ormore applications that include voice communications such as standardtelephony applications, voice-over-Internet Protocol (VoIP)applications, local gaming, Internet gaming, email, instant messaging,multimedia messaging, web browsing, audio/video recording, audio/videoplayback, audio/video downloading, playing of streaming audio/video,office applications such as databases, spreadsheets, word processing,presentation creation and processing and other voice and dataapplications. In conjunction with these applications, the real-time datacan include voice, audio, video and multimedia applications includingInternet gaming, etc. The non-real-time data can include text messaging,email, web browsing, file uploading and downloading, etc.

In an embodiment of the present invention, the access point 110 and/orthe communication devices include an integrated circuit, such as acombined voice, data and RF integrated circuit or other integratedcircuit that will be described in greater detail in association withFIGS. 2 and 3 that follow. These integrated circuits include an adaptiveRF transceiver that is operable to detect a packet transmission failure,to select one of a plurality of transmission failure causes, and toadjust at least one of a plurality of transmit parameters, based on theselected one of the plurality of transmission failure causes. In thisfashion, the RF transceiver can operate with a first set of transmitparameters and/or a first rate adjustment schedule when the RFtransceiver detects that transmission failures are caused by a standardnoise environment, such as a additive white Gaussian noise (AWGN)environment. However, when the RF transceiver detects other conditionssuch as burst noise or transmission failures caused by the receivingstation being non-responsive, such as in the case that the receivingstation is a multi-mode shared frequency device that operates indifferent modes in a shared frequency band (such a 802.11 compliantwireless local area network mode and a Bluetooth mode or other sharedfrequency modes, etc.) and is currently operating in a different modethan the transmitting station. In these cases, other transmit parametersand/or other rate adjustment schedules can be implemented that arebetter suited for efficient throughput under these alternativeconditions. Further details including many optional functions andfeatures of the invention will be described in greater detail inassociation with FIGS. 2-8 that follow.

FIG. 2 is a schematic block diagram of an embodiment of an integratedcircuit in accordance with the present invention. In particular, an RFintegrated circuit (IC) 70 is shown that implements communication device121, 123, 125 and/or 127 in conjunction with microphone 60,keypad/keyboard 58, memory 54, speaker 62, display 56, camera 76,antenna interface 52 and wireline port 64. In addition, voice data RF IC70 includes transceivers 73 and 75 with RF and baseband modules forformatting and modulating data into RF real-time data and/ornon-real-time data and transmitting this data and receiving similarlyformatted data via an antenna interfaces 72 and 74 and attachedantennas. While shown as separate components, transceivers 73 and 75,and antenna interfaces 72 and 74 may be optionally implemented with asingle transceiver, and antenna interface attached to a single antenna,particularly where the RF data 40 and RF voice 42 operate over a sharedfrequency band. Further, these modules may be implemented with partlydedicated and partly shared components to operate more efficiently.

Further, communication device 121, 123, 125 and/or 127 can be amulti-mode shared frequency device that operates in different modes in ashared frequency band. For instance, transceiver 73 may operate itselfin two or more modes of operation, such as in a Bluetooth and WLAN modeover a shared frequency spectrum. In addition, transceiver 75 mayoperate in GSM, UMTS, EDGE modes in another shared frequency spectrum.

RF IC 70 further includes an input/output module 71 with appropriateencoders and decoders for communicating via the wireline connection 28via wireline port 64, an optional memory interface for communicatingwith off-chip memory 54, a codec for encoding voice signals frommicrophone 60 into digital voice signals, a keypad/keyboard interfacefor generating data from keypad/keyboard 58 in response to the actionsof a user, a display driver for driving display 56, such as by renderinga color video signal, text, graphics, or other display data, and anaudio driver such as an audio amplifier for driving speaker 62 and oneor more other interfaces, such as for interfacing with the camera 76 orthe other peripheral devices.

Off-chip power management circuit 95 includes one or more DC-DCconverters, voltage regulators, current regulators or other powersupplies for supplying the RF IC 70 and optionally the other componentsof communication device 10 and/or its peripheral devices with supplyvoltages and or currents (collectively power supply signals) that may berequired to power these devices. Off-chip power management circuit 95can operate from one or more batteries, line power and/or from otherpower sources, not shown. In particular, off-chip power managementmodule can selectively supply power supply signals of differentvoltages, currents or current limits or with adjustable voltages,currents or current limits in response to power mode signals receivedfrom the RF IC 70. RF IC 70 optionally includes an on-chip powermanagement circuit 95′ for replacing the off-chip power managementcircuit 95.

In an embodiment of the present invention, the RF IC 70 is a system on achip integrated circuit that includes at least one processing device.Such a processing device, for instance, processing module 225, may be amicroprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on operational instructions. Theassociated memory may be a single memory device or a plurality of memorydevices that are either on-chip or off-chip such as memory 54. Such amemory device may be a read-only memory, random access memory, volatilememory, non-volatile memory, static memory, dynamic memory, flashmemory, and/or any device that stores digital information. Note thatwhen the RF IC 70 implements one or more of its functions via a statemachine, analog circuitry, digital circuitry, and/or logic circuitry,the associated memory storing the corresponding operational instructionsfor this circuitry is embedded with the circuitry comprising the statemachine, analog circuitry, digital circuitry, and/or logic circuitry.

In operation, the RF IC 70 executes operational instructions thatimplement one or more of the applications (real-time or non-real-time)attributed to communication devices 121, 123, 125, and/or 127 asdiscussed in conjunction with FIG. 1.

FIG. 3 is a schematic block diagram of an embodiment of an integratedcircuit in accordance with the present invention. In particular, an ICis shown that is used to implement access point 110. RF integratedcircuit (IC) 170 operates in conjunction with memory 154, antennainterface 172 and wireline port 164 to implement the functions andfeatures attributed to access point 110 as discussed in conjunction withFIG. 1. In addition, RF IC 170 includes transceiver 173 with RF andbaseband modules for formatting and modulating data into RF data 40 andtransmitting this data and receiving similarly formatted data via anantenna interfaces 172 the attached antenna. While not shown, accesspoint 110 optionally includes other modules such as microphone 60,keypad/keyboard 58, speaker 62, display 56, camera 76, of communicationdevices 121, 123, 125 or 127 along with one or more interface modulesand/or other modules depending on the type of device, the form factor,etc.

Further, access point 110 can itself be a multi-mode device thatoperates in different modes in a shared frequency band. For instance,transceiver 173 can operate in two or more modes of operation, such asin a Bluetooth and WLAN mode over a shared frequency spectrum Also,transceiver 173 can operate in adaptive fashion to detect a packettransmission failure, to select one of a plurality of transmissionfailure causes, and to adjust at least one of a plurality of transmitparameters, based on the selected one of the plurality of transmissionfailure causes.

Off-chip power management circuit 195 includes one or more DC-DCconverters, voltage regulators, current regulators or other powersupplies for supplying the RF IC 170 and optionally the other componentsof access point 110 and/or its peripheral devices with supply voltagesand or currents (collectively power supply signals) that may be requiredto power these devices. Off-chip power management circuit 195 canoperate from one or more batteries, line power and/or from other powersources, not shown. In particular, off-chip power management module canselectively supply power supply signals of different voltages, currentsor current limits or with adjustable voltages, currents or currentlimits in response to power mode signals received from the RF IC 170. RFIC 170 optionally includes an on-chip power management circuit 195′ forreplacing the off-chip power management circuit 195.

In an embodiment of the present invention, the RF IC 170 is a system ona chip integrated circuit that includes at least one processing device,such as processing module 225 described in conjunction with FIG. 2.

FIG. 4 is a schematic block diagram of an RF transceiver 125, such astransceivers 73, 75 and/or 173, which may be incorporated incommunication devices 121, 123, 125, 127 and/or access point 110. The RFtransceiver 125 includes an RF transmitter 129, and an RF receiver 127.The RF receiver 127 includes a RF front end 140, a down conversionmodule 142, and a receiver processing module 144. The RF transmitter 129includes a transmitter processing module 146, an up conversion module148, and a radio transmitter front-end 150.

As shown, the receiver and transmitter are each coupled to an antennathrough an off-chip antenna interface 171 and a diplexer (duplexer) 177,that couples the transmit signal 155 to the antenna to produce outboundRF signal 151 and couples inbound signal 152 to produce received signal153. While not shown, a transmit/receive switch can be implemented inplace of diplexer 177. Further, while a single antenna is represented,the receiver and transmitter may each use separate antennas that eachinclude one or more antennas. Each of the antennas may be fixed,programmable, and antenna array or other antenna configuration. Further,the antenna structure of the wireless transceiver may depend on theparticular standard(s) to which the wireless transceiver is compliantand the applications thereof.

In operation, the transmitter receives outbound data 162 from a hostdevice or other source via the transmitter processing module 146. Thetransmitter processing module 146 processes the outbound data 162 inaccordance with a particular wireless communication standard (e.g., IEEE802.11, Bluetooth, RFID, GSM, CDMA, et cetera) to produce baseband orlow intermediate frequency (IF) transmit (TX) signals 164. The basebandor low IF TX signals 164 may be digital baseband signals (e.g., have azero IF) or digital low IF signals, where the low IF typically will bein a frequency range of one hundred kilohertz to a few megahertz. Notethat the processing performed by the transmitter processing module 146can include, but is not limited to, scrambling, encoding, puncturing,mapping, modulation, and/or digital baseband to IF conversion. Furthernote that the transmitter processing module 146 may be implemented usinga shared processing device, individual processing devices, or aplurality of processing devices and may further include memory. Such aprocessing device implements one or more of its functions viamicroprocessor, micro-controller, digital signal processor,microcomputer, central processing unit, field programmable gate array,programmable logic device, state machine, logic circuitry, analogcircuitry, digital circuitry, and/or any device that manipulates signals(analog and/or digital) based on operational instructions. The memorymay be a single memory device or a plurality of memory devices. Such amemory device may be a read-only memory, random access memory, volatilememory, non-volatile memory, static memory, dynamic memory, flashmemory, and/or any device that stores digital information. Note thatwhen the processing module 146 implements one or more of its functionsvia a state machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory storing the corresponding operational instructionsis embedded with the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry.

The up conversion module 148 includes a digital-to-analog conversion(DAC) module, a filtering and/or gain module, and a mixing section. TheDAC module converts the baseband or low IF TX signals 164 from thedigital domain to the analog domain. The filtering and/or gain modulefilters and/or adjusts the gain of the analog signals prior to providingit to the mixing section. The mixing section converts the analogbaseband or low IF signals into up converted signals 166 based on atransmitter local oscillation 168.

The radio transmitter front end 150 includes a power amplifier and mayalso include a transmit filter module. The power amplifier amplifies theup converted signals 166 to produce outbound RF signals 151, which maybe filtered by the transmitter filter module, if included. The antennastructure transmits the outbound RF signals 151 to a targeted devicesuch as a RF tag, base station, an access point and/or another wirelesscommunication device.

The receiver receives inbound RF signals 152 via the antenna throughoff-chip antenna interface 171 that operates to process the inbound RFsignal 152 into received signal 153 for the receiver front-end 140. Thedown conversion module 142 includes a mixing section, an analog todigital conversion (ADC) module, and may also include a filtering and/orgain module. The mixing section converts the desired RF signal 154 intoa down converted signal 156 that is based on a receiver localoscillation 158, such as an analog baseband or low IF signal. The ADCmodule converts the analog baseband or low IF signal into a digitalbaseband or low IF signal. The filtering and/or gain module high passand/or low pass filters the digital baseband or low IF signal to producea baseband or low IF signal 156. Note that the ordering of the ADCmodule and filtering and/or gain module may be switched, such that thefiltering and/or gain module is an analog module.

The receiver processing module 144 processes the baseband or low IFsignal 156 in accordance with a particular wireless communicationstandard (e.g., IEEE 802.11, Bluetooth, RFID, GSM, CDMA, et cetera) toproduce inbound data 160. The processing performed by the receiverprocessing module 144 includes, but is not limited to, digitalintermediate frequency to baseband conversion, demodulation, demapping,depuncturing, decoding, and/or descrambling. Note that the receiverprocessing modules 144 may be implemented using a shared processingdevice, individual processing devices, or a plurality of processingdevices and may further include memory. Such a processing device canimplement one or more of its functions via a microprocessor,micro-controller, digital signal processor, microcomputer, centralprocessing unit, field programmable gate array, programmable logicdevice, state machine, logic circuitry, analog circuitry, digitalcircuitry, and/or any device that manipulates signals (analog and/ordigital) based on operational instructions. The memory may be a singlememory device or a plurality of memory devices. Such a memory device maybe a read-only memory, random access memory, volatile memory,non-volatile memory, static memory, dynamic memory, flash memory, and/orany device that stores digital information. Note that when the receiverprocessing module 144 implements one or more of its functions via astate machine, analog circuitry, digital circuitry, and/or logiccircuitry, the memory storing the corresponding operational instructionsis embedded with the circuitry comprising the state machine, analogcircuitry, digital circuitry, and/or logic circuitry.

In operation, receiver processing module 144 is operable to detect apacket transmission failure from a remote station, such as bydetermining that a packet transmitted by RF transceiver 125 was notacknowledged. Receiver processing module 144 provides feedback data 145to transmitter processing module 146 that selects one of a plurality oftransmission failure causes for the packet transmission failure, andadjusts at least one of a plurality of transmit parameters used togenerate transmit signal 155, based on the selected one of the pluralityof transmission failure causes. While shown as separate modules,receiver processing module 144 and transmitter processing module 146 canbe implemented using a shared processor, such as processing module 225.As such the steps performed by receiver processing module 144 andtransmitter processing module 146 can be shifted, to providefunctionality of one device to the other, within the broad scope of thepresent invention.

In an embodiment of the present invention, the feedback data 145includes a bit error rate, packet error rate, failure statistics such asa mean time between packet transmission failures, median time betweenpacket transmission failures a variance in the time between packettransmission failures or other statistics, a distribution of packettransmission failures, timing profile of packet transmission failures,and/or other packet transmission failure parameters that indicatecurrent and/or historical data relating to packet transmission failures.Feedback data can also include status feedback received from a remotestation in communication with RF transceiver 125. Such status data caninclude battery status, power status, trouble status, a mode status thatindicates that a particular remote station is a multi-mode sharedfrequency device that is capable of switching to an alternative mode ormore specific mode status data that indicates a coming change or modes,a mode schedule or other data relating to mode changes.

Feedback data 145 can be aggregated for all remote stations that are incommunication with RF transceiver 125. In the alternative, feedback data145 can be determined separately for each remote station incommunication with RF transceiver 125 so that RF transceiver 125 canoptionally determine different packet transmission failure causes forpacket transmission failures experienced in communications sent todifferent devices. For instance, a particular remote station may besubject to burst interference caused by a relatively low powerinterference source that is located close to this remote station butfarther away from the RF transceiver 125 and the other remote stationsin communication with the RF transceiver, while the operation of otherremote stations may be governed predominately by AWGN. Further a remotestation can be a multi-mode shared spectrum device that has switchedmodes and be effectively “dead” for a period of time with packettransmission failures occurring for all transmissions from RFtransceiver 125 during this period, while the other remote stations inthe area are operating normally.

The provision of feedback data 145 by receiver processing module 144 canbe performed whenever a packet transmission failure occurs or based onan event trigger such as the determination that a change in feedbackdata has occurred that indicates a potential that a change in noise,interference or other transmission failure causes of the RF transceiver125. For example, such a triggering event can be the generated by thenumber of packet transmission failures since the last triggering eventor a time window or other time period exceeding a threshold. In anotherexample, an long-term average packet error rate can be maintained andcompared with a short-term average packet error rate. The deviation ofthese short and long term packet error rates by an amount greater than athreshold can be used to indicate a change in packet error rate and apotential change in the cause of packet transmission failure.

The feedback data 145 can be analyzed by the transmitter processingmodule 146 and the selection of one of a plurality of one of theplurality of transmission failure causes can be performed based onchanges in feedback data. For instance, feedback data 145 can beanalyzed to determine if a feedback data 145 indicates that one of theplurality of transmission failure causes has occurred that is differentthan the current transmission failure cause that has been selected. Forinstance, the transmitter processing module 146 can analyze feedbackdata 145 to determine transmission failure causes such as the presenceof burst interference or other interference or a change in other noiseparameters of the environment for a particular remote station or aplurality of remote stations. In addition, transmitter processing module146 can analyze feedback data 145 to determine if one or more remotestations may be or are, multi-mode shared frequency devices that haveswitched modes to be inactive, indicating a new transmission failurecause for these remote stations.

In an embodiment of the present invention, transmitter processing module146, based on feedback data 145 or other data, maintains a mode statusfor each remote station to indicate if that remote station is amulti-mode device and/or that indicates whether or not that particularremote station is in a mode that allows communication with RFtransceiver 125. As indicated above, the mode status of a remote stationcan be determined based on a direct indication of the mode statusreceived in communication from remote station itself. Also, mode statuscan be determined inferentially based on acknowledgements received fromthe remote station of successful packet transmissions or packettransmission failures for packets sent to the remote station. Forinstance, the mode status of a remote station can be switched frominactive to active communication mode if feedback data 145 indicates apacket transmitted to the remote station has been successfullyacknowledged. Further, as will be discussed in greater detail inconjunction with FIG. 5, an analysis of a timing profile of packettransmission failures can indicate that a remote station that was anactive communication mode has switched to an inactive mode.

RF transceiver 125 has a plurality of transmit parameters that governthe rate, power, protocol and protocol parameters used to transmitoutbound data to one or more remote stations. Each transmit parameterhas a corresponding default value. For instance, RF transceiver 125 mayhave a rate adjustment schedule, that controls the transmit rate of RFtransceiver 125 based on a dynamic transmission adaptation algorithm,corresponding to a default case where packet transmission failures areattributed an AWGN environment. The transmit rate begins at the highestpossible value and is decreased after a rate adjustment threshold of npacket transmission failures is met or exceeded. In the event thatanother one of the plurality of transmission failure causes is selectedbased on the feedback data 145, changes in the transmit parameters aremade to correspond to the new transmission failure cause. For instance,data rates, rate adjustment thresholds, rate adjustment parametersand/or other aspects of a rate adjustment schedule can be modified,and/or retransmission delays, packet drop conditions, fragmentation orretransmission thresholds, or other transmission parameters can bemodified to maximize the throughput, or otherwise to increase theefficiency of the RF transmitter 125 based on these new conditions.

For example, should the transmission failure cause indicate burstinterference or a multi-mode remote station that has switched to aninactive mode, packet retransmissions to the effected station orstations can be delayed to allow queued transmission or retransmissionsto other remote stations to be transmitted, increasing the transmissionthroughput and to allow the burst to end or the multimode station toswitch modes again. Further, the rate adjustment schedule can bemodified to increase the number of failed retransmissions required todecrease the transmit rate, and/or to require not only a certain numberof failed retransmission attempts before the data rate is decreased, butalso to require or to increase a required duration before the data rateis decreased. This duration can be calculated based on expected burstinterference durations, measured burst error durations determined bymonitoring the timing profile of packet transmission failures, expectedtime periods remote stations may be in an inactive mode that can bedetermined a priori, based on a switching schedule or other informationprovided by the remote station itself, or also based on monitoring thetiming profile of packet transmission failures.

In this fashion, the transmit parameters of RF transceiver 125 can bemore effectively adapted to current conditions of the environment and/orthe conditions of the remote stations in communication with the RFtransceiver at any given time.

FIG. 5 is a time diagram in an embodiment of the present invention. Inparticular, in this embodiment, the features of the present inventionthat allow the selection of one of the plurality of failure causes and acorresponding adaptation of the transmit parameters are selectivelydisabled. A time profile is shown that indicates in graph 200 packettransmission attempts in communication by a communication device, suchas access point 110, to another communication device, such ascommunication device 121, 123, 125 or 127 in a default condition wherethe cause of retransmission failures is assumed to be the standard AWGNcase. It is noted that the time represented in this figure is not drawnto scale, but is rather presented to be illustrative of the conceptsthat aid in the understanding of certain aspects and embodiments of thepresent invention. In this example, communication device 121, 123, 125or 127 is a multimode shared spectrum device that is active during thetime periods indicated by mode 1 and is inactive during the time periodindicated by mode 2. The circles on graph 200 represent packettransmission or retransmissions. Graph 202 indicates, by X's on thegraph, the packet transmissions that failed over the same time period.As is shown, mode 1 times correspond to low failure periods where mostor all packet transmission attempts do not result in packet transmissionfailures. The period of mode 2 corresponds to a high failure periodsince the communication device 121, 123, 125 or 127 is inactive withrespect to communications with access point 110. Access point 110continues to retransmit packets during the high failure period, eventhough communication device 121, 123, 125 or 127 is inactive. The rateadjustment schedule of access point 110 could potentially decrease thetransmit data rate during this time, lowering the throughput ofcommunications when communication device 121, 123, 125 or 127 switchesback to active status in mode 1. Further, access point 110 wastes timeand bandwidth trying to retransmit to communication device 121, 123, 125or 127 during mode 2 that could be used by access point 110 to sendpackets to other remote stations.

FIG. 7 is a time diagram in accordance with an embodiment of the presentinvention In particular, in this embodiment, the features of the presentinvention that allow the selection of one of the plurality of failurecauses and a corresponding adaptation of the transmit parameters areselectively enabled. A time profile is shown that indicates in graph200′ packet transmission attempts in communication by a communicationdevice, such as access point 110, to another communication device, suchas communication device 121, 123, 125 or 127 in a default conditionwhere the cause of retransmission failures is assumed to be the standardAWGN case. It is noted that the time represented in this figure is notdrawn to scale, but is rather presented to be illustrative of theconcepts that aid in the understanding of certain aspects andembodiments of the present invention. In this example, communicationdevice 121, 123, 125 or 127 is a multimode shared spectrum device thatis active during the time periods indicated by mode 1 and is inactiveduring the time period indicated by mode 2. The circles on graph 200′represent packet transmission or retransmissions. Graph 202′ indicates,by X's on the graph, the packet transmissions that failed over the sametime period. As is shown, mode 1 times correspond to low failure periodswhere most or all packet transmission attempts do not result in packettransmission failures. During the period of mode 2 corresponds to a highfailure period since the communication device 121, 123, 125 or 127 isinactive with respect to communications with access point 110.

Unlike the case shown in FIG. 6, Access point 110 has noted, based oninformation transmitted by communication device 121, 123, 125 or 127,that this remote station is capable of multi-mode communication.Communication device monitors the timing profile and analyzes feedbackdata based on packet transmission failures during the high failureperiod to determine that a new cause of transmission failure, the switchof communication device 121, 123, 125 or 127 to mode 2 has occurred. Inresponse, access point 110 delays the retransmission of packets tocommunication device 121, 123, 125 or 127 by a delay period 210 andmodifies the rate adjustment schedule to require not only mretransmissions, but the expiration of a time period T, as conditions todecrease the data rate for transmissions to communication device 121,123, 125 or 127. During this delay period 210, communication devicesends packets to other remote stations. After the delay period 210,communication station 45 retransmits a packet that is acknowledged bycommunication device 121, 123, 125 or 127. Access point 110 thencontinues to transmit to communication device 121, 123, 125 or 127without a decrease in transmit data rate. Indication of theacknowledgement in feedback data 145 allows communication device todetermine that communication device 121, 123, 125 or 127 has reenteredactive status and in response the cause of packet retransmission failureis returned to the default position of AGWN with correspondingmodification to the transmit parameters. This can occur upon the receiptof the acknowledgement or held until the next packet transmissionfailure.

While the examples presented in conjunction with FIGS. 5 and 6 presentseveral alternative features of the present invention, a wider range ofalternatives and embodiments are likewise possible as have been alsodiscussed.

FIG. 7 is a flowchart representation of a method in accordance with anembodiment of the present invention. In particular a method is presentedfor use with one or more features or functions presented in conjunctionwith FIGS. 1-6, such as method for use in an radio frequency (RF)transceiver coupled to transmit an outbound RF signal in accordance witha plurality of transmit parameters to at least one remote station andreceive a inbound RF signal from the at least one remote station. Instep 400, a packet transmission failure is detected. In step 410, one ofa plurality of transmission failure causes is selected. In step 420, atleast one of a plurality of transmit parameters is adjusted, based onthe selected one of the plurality of transmission failure causes.

In an embodiment of the present invention, step 410 includes analyzingfeedback data generated by the RF transceiver based on the inbound RFsignal. Analyzing feedback data can include monitoring a timing profileof a plurality of transmission failures. The feedback data can includefailure statistics. The remote station includes a multi-mode sharedfrequency transceiver that can operate in a first mode for communicationwith the RF transceiver and a second mode that precludes communicationwith the RF transceiver. Step 420 can include determining the multi-modeshared frequency status of the remote station and whether the remotestation is operating in a first or second mode of operation.

In an embodiment of the present invention, step 420 can includeincreasing a retransmission delay for retransmissions to the remotestation, adjusting a rate adjustment parameter. The plurality oftransmit parameters can includes a first rate adjustment scheduleparameter that modifies a rate adjustment schedule that controls atransmit rate of the RF transceiver. The first rate adjustment scheduleparameter can correspond to a number of failed retransmissions requiredto decrease the transmit rate. The plurality of transmit parameters caninclude a second rate adjustment schedule parameter that modifies therate adjustment schedule that controls the transmit rate of the RFtransceiver. The second rate adjustment schedule parameter cancorrespond to a duration of failed retransmissions required to decreasethe transmit rate.

FIG. 8 is a flowchart representation of a method in accordance with anembodiment of the present invention. In particular, a method ispresented that includes several steps described in conjunction with FIG.7 that are referred to by common reference numerals. In addition, step390 of transmitting, from the remote station, a data packet to the RFtransceiver that indicates a multi-mode shared frequency status.

As may be used herein, the terms “substantially” and “approximately”provides an industry-accepted tolerance for its corresponding termand/or relativity between items. Such an industry-accepted toleranceranges from less than one percent to fifty percent and corresponds to,but is not limited to, component values, integrated circuit processvariations, temperature variations, rise and fall times, and/or thermalnoise. Such relativity between items ranges from a difference of a fewpercent to magnitude differences. As may also be used herein, theterm(s) “coupled to” and/or “coupling” and/or includes direct couplingbetween items and/or indirect coupling between items via an interveningitem (e.g., an item includes, but is not limited to, a component, anelement, a circuit, and/or a module) where, for indirect coupling, theintervening item does not modify the information of a signal but mayadjust its current level, voltage level, and/or power level. As mayfurther be used herein, inferred coupling (i.e., where one element iscoupled to another element by inference) includes direct and indirectcoupling between two items in the same manner as “coupled to”. As mayeven further be used herein, the term “operable to” indicates that anitem includes one or more of power connections, input(s), output(s),etc., to perform one or more its corresponding functions and may furtherinclude inferred coupling to one or more other items. As may stillfurther be used herein, the term “associated with”, includes directand/or indirect coupling of separate items and/or one item beingembedded within another item. As may be used herein, the term “comparesfavorably”, indicates that a comparison between two or more items,signals, etc., provides a desired relationship. For example, when thedesired relationship is that signal 1 has a greater magnitude thansignal 2, a favorable comparison may be achieved when the magnitude ofsignal 1 is greater than that of signal 2 or when the magnitude ofsignal 2 is less than that of signal 1.

The present invention has also been described above with the aid ofmethod steps illustrating the performance of specified functions andrelationships thereof. The boundaries and sequence of these functionalbuilding blocks and method steps have been arbitrarily defined hereinfor convenience of description. Alternate boundaries and sequences canbe defined so long as the specified functions and relationships areappropriately performed. Any such alternate boundaries or sequences arethus within the scope and spirit of the claimed invention.

The present invention has been described above with the aid offunctional building blocks illustrating the performance of certainsignificant functions. The boundaries of these functional buildingblocks have been arbitrarily defined for convenience of description.Alternate boundaries could be defined as long as the certain significantfunctions are appropriately performed. Similarly, flow diagram blocksmay also have been arbitrarily defined herein to illustrate certainsignificant functionality. To the extent used, the flow diagram blockboundaries and sequence could have been defined otherwise and stillperform the certain significant functionality. Such alternatedefinitions of both functional building blocks and flow diagram blocksand sequences are thus within the scope and spirit of the claimedinvention. One of average skill in the art will also recognize that thefunctional building blocks, and other illustrative blocks, modules andcomponents herein, can be implemented as illustrated or by discretecomponents, application specific integrated circuits, processorsexecuting appropriate software and the like or any combination thereof.

What is claimed is:
 1. A circuit comprising: a transceiver coupled totransmit an outbound signal via a first network protocol and inaccordance with a plurality of transmit parameters, to at least oneremote station and receive a inbound signal from the at least one remotestation, the transceiver operable to detect a packet transmissionfailure, to select one of a plurality of transmission failure causes,and to adjust at least one of a plurality of transmit parameters, basedon the selected one of the plurality of transmission failure causes,wherein the adjustment of the at least one of the plurality of transmitparameters includes adjusting a first rate adjustment parameter thatcorresponds to a number of failed retransmissions required to decreasethe transmit rate and a second rate adjustment parameter that controlsthe transmit rate of the transceiver; wherein selection of one of theplurality of transmission failure causes is based on determining thatthe at least one remote station is a multi-mode shared frequency devicecommunicating via a second network protocol, wherein the first networkprotocol and the second network protocol are each different ones of: awireless telephony protocol and a wireless local area network protocol;wherein the selection of one of the plurality of transmission failurecauses includes analyzing feedback data generated by the transceiverbased on the inbound signal and by monitoring a timing profile of aplurality of transmission failures; and wherein the remote stationincludes a multi-mode shared frequency transceiver that can operate in afirst mode for communication with the transceiver and a second mode thatprecludes communication with the transceiver.
 2. The circuit of claim 1wherein analyzing the feedback data includes analyzing failurestatistics.
 3. The circuit of claim 1 wherein the at least one of theplurality of transmit parameters includes a first rate adjustmentschedule parameter that modifies a rate adjustment schedule thatcontrols a transmit rate of the transceiver.
 4. The circuit of claim 1wherein the remote station transmits a data packet to the transceiverthat indicates a multi-mode shared frequency status.
 5. The circuit ofclaim 1 wherein the selection of one of the plurality of transmissionfailure causes includes determining that the remote station is operatingin the second mode.
 6. The circuit of claim 1 wherein the adjustment ofthe at least one of the plurality of transmit parameters includesincreasing a retransmission delay for retransmissions to the remotestation.
 7. A method for use in a transceiver coupled to transmit anoutbound signal in accordance with a plurality of transmit parameters toat least one remote station and receive a inbound signal from the atleast one remote station, the method comprising: detecting a packettransmission failure; determining that the at least one remote stationis a multi-mode shared frequency device for operation selectively in afirst mode for communication with the transceiver and in a second modethat precludes communication with the transceiver, wherein the firstmode and the second mode are each different ones of: a wirelesstelephony mode that includes communication via a wireless telephonyprotocol and a wireless local area network mode that includescommunication via a wireless local area network protocol; selecting oneof a plurality of transmission failure causes, based on a determinationthat the at least one remote station is operating in the second mode byanalyzing feedback data generated by the transceiver based on theinbound signal and monitoring a timing profile of a plurality oftransmission failures; and adjusting at least one of a plurality oftransmit parameters, based on the selected one of the plurality oftransmission failure causes, wherein the adjustment of the at least oneof the plurality of transmit parameters includes adjusting a first rateadjustment parameter that corresponds to a number of failedretransmissions required to decrease the transmit rate and a second rateadjustment parameter that controls the transmit rate of the transceiver.8. The method of claim 7 wherein analyzing the feedback data includesanalyzing failure statistics.
 9. The method of claim 7 furthercomprising the step of: transmitting, from the remote station, a datapacket to the transceiver that indicates a multi-mode shared frequencystatus.
 10. The method of claim 7 wherein the step of selecting one ofthe plurality of transmission failure causes includes determining thatthe remote station is operating in the second mode.
 11. A circuitcomprising: a transceiver coupled to transmit an outbound signal via afirst network protocol and in accordance with a plurality of transmitparameters, to at least one remote station and receive a inbound signalfrom the at least one remote station, the transceiver operable to detecta packet transmission failure, to select one of a plurality oftransmission failure causes, and to adjust at least one of a pluralityof transmit parameters, based on the selected one of the plurality oftransmission failure causes, wherein the adjustment of the at least oneof the plurality of transmit parameters includes adjusting a first rateadjustment parameter that corresponds to a number of failedretransmissions required to decrease the transmit rate and a second rateadjustment parameter that controls the transmit rate of the transceiver;wherein selection of one of the plurality of transmission failure causesis based on determining that the at least one remote station is amulti-mode shared frequency device communicating via a second networkprotocol, wherein the first network protocol and the second networkprotocol are each different ones of: a wireless telephony protocol and awireless local area network protocol; wherein the selection of one ofthe plurality of transmission failure causes includes analyzing feedbackdata generated by the transceiver based on the inbound signal and byanalyzing failure statistics; wherein the remote station includes amulti-mode shared frequency transceiver that can operate in a first modefor communication with the transceiver and a second mode that precludescommunication with the transceiver.
 12. The circuit of claim 11 whereinthe adjustment of the at least one of the plurality of transmitparameters includes increasing a retransmission delay forretransmissions to the remote station.
 13. The circuit of claim 11wherein the second rate adjustment parameter corresponds to a durationof failed retransmissions required to decrease the transmit rate.
 14. Acircuit comprising: a transceiver coupled to transmit an outbound signalvia a first network protocol and in accordance with a plurality oftransmit parameters, to at least one remote station and receive ainbound signal from the at least one remote station, the transceiveroperable to detect a packet transmission failure, to select one of aplurality of transmission failure causes, and to adjust at least one ofa plurality of transmit parameters, based on the selected one of theplurality of transmission failure causes, wherein the adjustment of theat least one of the plurality of transmit parameters includes adjustinga first rate adjustment parameter that corresponds to a number of failedretransmissions required to decrease the transmit rate and a second rateadjustment parameter corresponds to a duration of failed retransmissionsrequired to decrease the transmit rate and controls the transmit rate ofthe transceiver; wherein selection of one of the plurality oftransmission failure causes is based on determining that the at leastone remote station is a multi-mode shared frequency device communicatingvia a second network protocol, wherein the first network protocol andthe second network protocol are each different ones of: a wirelesstelephony protocol and a wireless local area network protocol; whereinthe selection of one of the plurality of transmission failure causesincludes analyzing feedback data generated by the transceiver based onthe inbound signal and by monitoring a timing profile of a plurality oftransmission failures; and wherein the remote station includes amulti-mode shared frequency transceiver that can operate in a first modefor communication with the transceiver and a second mode that precludescommunication with the transceiver.
 15. The circuit of claim 14 whereinanalyzing the feedback data includes analyzing failure statistics. 16.The circuit of claim 14 wherein the at least one of the plurality oftransmit parameters includes a first rate adjustment schedule parameterthat modifies a rate adjustment schedule that controls a transmit rateof the transceiver.
 17. The circuit of claim 14 wherein the remotestation transmits a data packet to the transceiver that indicates amulti-mode shared frequency status.
 18. The circuit of claim 14 whereinthe selection of one of the plurality of transmission failure causesincludes determining that the remote station is operating in the secondmode.
 19. The circuit of claim 14 wherein the adjustment of the at leastone of the plurality of transmit parameters includes increasing aretransmission delay for retransmissions to the remote station.
 20. Themethod of claim 7 wherein the second rate adjustment parametercorresponds to a duration of failed retransmissions required to decreasethe transmit rate.